gj. BOARD OP AGRICULTURE. 



a quarter to a half inch, Tve secure by a liberal application both 

 sufficient immetliate effect, and also endurance for a considerable 

 term of years. This is, on the whole, the more economical way to 

 apply them in most instances. Where there is a deficiency of phos- 

 phate in the soil, the application of crushed bone is the cheapest 

 mode in which the want can be supplied, unless in some instances 

 where leached ashes can be had at low price, in which case it can 

 be supplied thus at even less cost, but crushed bone will supply it 

 decidedly cheaper than by the use of low priced varieties of guano, 

 whose efficacy consists principally in the phosphate they contain, as 

 the Mexican, or by the use of the superphosphates of commerce. 



But in estimating the value of bone-dust as a fertilizing material, 

 the organic or animal matter should by no means be lost sight of 

 If phosphate of lime were the only ingredient of value, bones could 

 easily be burned and reduced to powder, as none of the phosphate 

 would thus be lost, but the or^janic matter which wovild be dissipated 

 contains no less than eighteen per cent, of nitrogen, and is substan- 

 tially similar in chemical composition to hair, horn and wool, and 

 differs from muscle and blood chiefly in containing less water, dried 

 blood and dried muscle being almost exactly the same as to their 

 chemical constituents and properties. 



All these substances are well known to be among the most power- 

 ful of fertilizers, and their value depends mainly upon the nitrogen 

 they afford. It will of course be borne in mind that the office or 

 function of nitrogen and of phosphoric acid in the nutrition of 

 plants, is essentially distinct. Neither can take the place of the 

 other, and neither can be dispensed with. Nitrogen induces rapid 

 and luxuriant growth of the plant — phosphoric acid assists in the 

 formation and ripening of seed. If nitrogen be abundant, a luxuri- 

 ant straAV could be grown ; but if phosphoric acid be wanting, the 

 head could not fill with grain. On the other hand, if nitrogen be 

 absent, or the plant could obtain it only from the atmosphere, there 

 would not be sufficient power, vigor or vitality to induce growth and 

 form seed, even if phosphoric acid be abundant. 



The application of bone-dust to agricultural practice in Maine 

 has been quite limited hitherto. I noticed remarkable proof of its 

 efficacy and value in several of the easternmost towns of Washing- 

 ton county last summer, where it has been used for ten years past, 



